Estudio sobre la corrosión en resquicios y picaduras en los aceros inoxidables AISI 304 y AISI 316

En este artículo se realiza una presentación de los trabajos de investigación que se están realizando en el ámbito de Ciencia de los Materiales en el Centro Universitario de la Defensa del Ejército del Aire en San Javier. Actualmente se están desarrollando estudios sobre cómo afecta la corrosión a los aceros inoxidables grado AISI 304 y AISI 316 de acuerdo con la normativa ASTM G48-11. El mecanismo de corrosión es por picaduras y resquicios.Centro Universitario de la Defensa. Escuela de Turismo de Cartagena. Escuela Técnica Superior de Ingeniería Industrial UPCT. Escuela Técnica Superior de Ingeniería de Telecomunicación (ETSIT). Escuela de Ingeniería de Caminos y Minas (EICM). Escuela de Arquitectura e Ingeniería de Edificación (ARQ&IDE). Parque Tecnológico de Fuente Álamo. Navantia. Campus Mare Nostrum. Estación Experimental Agroalimentaria Tomás Ferr

Pressure-Driven Metallization in Hafnium Diselenide

The quest for new transition metal dichalcogenides (TMDs) with outstanding electronic properties operating at ambient conditions draws us to investigate the 1T-HfSe2 polytype under hydrostatic pressure. Diamond anvil cell (DAC) devices coupled to in- situ synchrotron X-ray, Raman and optical (VIS-NIR) absorption experiments along with density functional theory (DFT) based calculations prove that: (i) bulk 1T-HfSe2 exhibits strong structural and vibrational anisotropies, being the interlayer direction especially sensitive to pressure changes, (ii) the indirect gap of 1T-HfSe2 trend to vanish by a -0.1 eV/GPa pressure rate, slightly faster than MoS2 or WS2, (iii) the onset of the metallic behavior appears at Pmet ~10 GPa, which is to date the lowest pressure among common TMDs, and finally (iv) the electronic transition is explained by the bulk modulus B0-Pmet correlation, along with the pressure coefficient of the band gap, in terms of the electronic overlap between chalcogenide p-type and metal d-type orbitals

Randomized-controlled trial of the DIALIVE liver dialysis device vs. standard of care in patients with acute-on-chronic liver failure

BACKGROUND AND AIMS: Acute on chronic liver failure (ACLF) is characterized by severe systemic inflammation, multi-organ failure and high mortality rates. Its treatment is an urgent unmet need. DIALIVE is a novel liver dialysis device that aims to exchange d ysfunctional albumin and remove damage- and pathogen-associated molecular patterns. This first-in-man randomized, controlled clinical trial was performed with the primary aim of assessing its safety in ACLF patients with secondary aims to evaluate its clinical effects, device performance and effect on pathophysiologically-relevant biomarkers. METHODS: 32 alcoholic cirrhosis patients with ACLF were included. Patients were treated with DIALIVE for up to 5-days and end points were assessed at Day-10. Safety was assessed in all patients (n=32). The secondary aims were assessed in a pre-specified subgroup that had at least 3-treatment sessions with DIALIVE (n=30). RESULTS: There were no significant differences in 28-day mortality or occurrence of serious adverse events between the groups. Significant reduction in the severity of endotoxemia and improvement in albumin function was observed in DIALIVE group, which translated into a significant reduction in the CLIF-C (Chronic Liver Failure consortium) organ failure (p=0.018) and CLIF-C ACLF scores (p=0.042) at Day-10. Time to resolution of ACLF was significantly faster in DIALIVE group (p=0.036). Biomarkers of systemic inflammation such as IL-8 (p=0.006), cell death [cytokeratin-18: M30 (p=0.005) and M65 (p=0.029)], endothelial function [asymmetric dimethylarginine (p=0.002)] and, ligands for toll-like receptor 4 (p=0.030) and inflammasome (p=0.002) improved significantly in DIALIVE group. CONCLUSIONS: These data indicate that DIALIVE appears to be safe and impacts positively on prognostic scores and pathophysiologically relevant biomarkers in patients with ACLF. Larger, adequately powered studies are warranted to further confirm its safety and efficacy. LAY SUMMARY: This is the first-in-man clinical trial which tested DIALIVE, a novel liver dialysis device for the treatment of liver cirrhosis and acute on chronic liver failure, a condition associated with severe inflammation, organ failures and a high risk of death. The study met the primary end point confirming DIALIVE system to be safe. Additionally, it reduced inflammation with improved clinical parameters. It did not, however, reduce mortality in this small study and requires further larger clinical trials to re-confirm its safety and evaluate efficacy. CLINICAL TRIAL NUMBER: NCT03065699

1,4-Dioxepanes, 1,4-Oxathiepanes, and 1,4-Dithiepanes

© 2022 Elsevier Ltd. All rights reserved.The focus of this article has been the progress on aromatic systems containing two of the heteroatoms O or S in 1,4-relative positions. Firstly, the reactivity of 1,4-dioxepanes, 1,4-oxathiepanes and 1,4-dithiepanes are collected and then, the syntheses of these heterocycles are summarized. Prominent synthetic methods have often been driven by a desire to prepare new materials and compounds with biological activities

SimKinet: A free educational tool based on an electrical analogy to solve chemical kinetic equations.

In this article we introduce the software SimKinet, a free tool specifically designed to solve systems of differential equations without any programming skill. The underlying method is the so-called Network Simulation Method, which designs and solves an electrical network equivalent to the mathematical problem. SimKinet is versatile, fast, presenting a real user-friendly interface, and can be employed for both educational and researching purposes. It is particularly useful in the first courses of different scientific degrees, mainly Chemistry and Physics, especially when facing non-analytic or complex-dynamics problems. Moreover, SimKinet would help students to understand fundamental concepts, being an opportunity to improve instruction in Chemistry, Mathematics, Physics and other Sciences courses, with no need of advanced knowledge in differential equations. The potency of SimKinet is demonstrated via two applications in chemical kinetics: the photochemical destruction of stratospheric ozone and the chaotic dynamics of the peroxidase-oxidase reaction

Chemodivergent Conversion of Ketenimines Bearing Cyclic Dithioacetalic Units into Isoquinoline-1-thiones or Quinolin-4-ones as a Function of the Acetalic Ring Size

C-Alkoxycarbonyl-C-phenyl-N-aryl ketenimines bearing 1,3-dithiolan-2-yl or 1,3-dithian-2-yl substituents at ortho position of the C-phenyl ring, respectively, transform into isoquino-line-1-thiones and quinolin-4-ones under thermal treatment in toluene solution. The formation of isoquinolinethiones involves a rare degradation of the 1,3-dithiolane ring, whereas, in contrast, the 1,3-dithiane ring remains intact during the reaction course leading to quinolin-4-ones. Computational density functional theory results support that the kinetically favorable mechanism for the formation of isoquinoline-l-thiones proceeds through a [1,5]-hydride shift/6 pi-electrocyclization cascade, followed by a thiirane extrusion process. Alternative mechanistic paths showing interesting electronic reorganization processes have been also scrutinized but resulted not competitive on energetic grounds

Tandem processes promoted by a hydrogen shift in 6-arylfulvenes bearing acetalic units at ortho position: a combined experimental and computational study

6-Phenylfulvenes bearing (1,3-dioxolan or dioxan)-2-yl substituents at ortho position convert into mixtures of 4- and 9-(hydroxy)alkoxy-substituted benz[f]indenes as result of cascade processes initiated by a thermally activated hydrogen shift. Structurally related fulvenes with non-cyclic acetalic units afforded mixtures of 4- and 9-alkoxybenz[f]indenes under similar thermal conditions. Mechanistic paths promoted by an initial [1,4]-, [1,5]-, [1,7]- or [1,9]-H shift are conceivable for explaining these conversions. Deuterium labelling experiments exclude the [1,4]-hydride shift as the first step. A computational study scrutinized the reaction channels of these tandem conversions starting by [1,5]-, [1,7]- and [1,9]-H shifts, revealing that this first step is the rate-determining one and that the [1,9]-H shift is the one with the lowest energy barrier

IV Congreso Nacional de i+d en Defensa y Seguridad: Actas

En el mes de noviembre de este a˜no 2016 se celebra la cuarta edición del Congreso Nacional de I+D en Defensa y Seguridad (DESEI+d) en la Academia General del Aire de San Javier. Este Congreso ha sido impulsado por la Subdirección General de Planificación, Tecnología e Innovación (SDGPLATIN) perteneciente a la Dirección de Armamento y Material (DGAM) del Ministerio de Defensa, que forma parte del Comité Organizador junto con el Centro Universitario de la Defensa de San Javier, como anfitrión en esta edición, la Dirección General de Reclutamiento y Enseñanza Militar, los Centros Universitarios de la Defensa de Marín, Zaragoza y Madrid e Isdefe. Este Congreso se ha venido celebrando de forma anual desde el año 2013, el primer año en Madrid y los posteriores en Zaragoza y Marín respectivamente. Su finalidad es crear un foro de referencia nacional donde se presenten las innovaciones tecnológicas que se llevan a cabo en cooperación entre los distintos agentes implicados en la I+D+i en el ámbito de la defensa y la seguridad (Universidades, Centros Universitarios de la Defensa, el Centro Universitario de la Guardia Civil, OPIs, empresas, laboratorios, etc.). Asimismo, sirve como medio de presentación y difusión de investigaciones y desarrollos existentes en el ámbito civil con resultados y metodologías innovadoras potencialmente aplicables a la defensa y seguridad nacional, y por tanto con potencial aplicación dual.Isdefe; Ayuntamiento de San Javier; Universidad Politécnica de Cartagena; Expal; ITP; inaer; Electrónica submarina Saes; Sidilab (Sistemas Didácticos De Laboratorio S. L.); Jasco y Proquilab

5-Alkenylthiazoles as In-Out Dienes in Polar [4+2] Cycloaddition Reactions

5-Alkenyl-2-aminothiazoles react as in-out dienes with a wide range of electron-poor dienophiles leading to the corresponding cycloaddition products in good to excellent yields. The [4+2] cycloadditions of 5-alkenyl-2-aminothiazoles can be classified as site-selective since only the diene moiety including the formal C-C double bond of the heterocycle and that of the side-chain is involved. Calculations of the HOMO energy values of representative 5-alkenyl-2-aminothiazoles are disclosed The cycloadditions are endo-selective with N-phenylmaleimide or maleic anhydride and regioselective when the reactions are conducted with non symmetrical dienophiles. Completely oxidized cycloadducts are obtained in the reactions of 5-alkenyl-2-aminothiazoles with naphthoquinone or DMAD. Unexpectedly, the reactions with PTAD are not stereospecific. A mechanism placed at the concerted/stepwise boundary is proposed

4-Alkenyl-2-aminothiazoles: Smart Dienes for Polar [4 + 2] Cycloadditions

An exhaustive investigation on the [4+2] cycloadditions of 4-alkenyl-2-aminothiazoles with a wide range of dienophiles has been carried out. 4-Alkenyl-2-aminothiazoles act as good in-out dienes reacting with dienophiles bearing electron-withdrawing groups. The heteroannulations, typically conducted under mild conditions, are endo-selective when cyclic dienophiles are employed and regioselective when the reactions are conducted with non symmetric dienophiles. The endo-selective processes presumably take place by concerted but highly asynchronous mechanisms. By contrast, the low levels of endo selectivity and the lack of stereospecificity in the reactions with certain acyclic dienophiles point to a stepwise mechanism with a zwitterion as the most plausible intermediate. The course of the reaction changes when the highly reactive PTAD and TCNE are used as dienophiles since only addition products are obtained. Calculations of the HOMO and LUMO energy values of representative 4-alkenyl-2-aminothiazoles and the results of π-facial diastereoselective processes by using chiral substrates are also disclosed